Beihai Tunnel (Nangan)

The Beihai Tunnel is one of Matsu’s most iconic military landmarks, originally constructed in 1968 as part of the Beihai Project to provide concealed berthing for guerrilla boats. Carved deep into the cliffs along the Tiebian coast, the tunnel features a grid-like waterway system stretching about 640 meters, with water levels rising and falling with the tide. Visitors can explore a 700-meter walking route, accessible only during low tide. Built under extremely challenging conditions with limited equipment, the project mobilized thousands of troops and took 820 days to complete. Today, the towering granite walls and shifting reflections inside the tunnel offer a powerful glimpse into Matsu’s wartime past.